Density Functional Theories in Quantum Chemistry

A review of the "local density" exchange-correlation approximation (LDA) in quantum chemistry is provided, with particular emphasis on the calculation of molecular bond energies, bond lengths, and vibrational frequencies. The LDA, surprisingly successful in itself, is improved even further by addition of so-called "gradient correction" terms, and following a very brief discussion of the history of gradient-corrected exchange-correlation approximations, recent work in this area is presented. Experience to date, and new results of the present work, indicate that beyond-LDA density functional theories yield molecular spectroscopic properties of near chemical accuracy, even in transition-metal systems, with minimal computational effort.